Grain drier



Patented June 17, 1952 UNITED STATES PATENT .OFFICE GRAIN DRIER Robert D. Applegate, Attica, Ind. 7 Application August 28, 194 8,Seria'l N 0. 46,633

This invention relates to a device for grain drying and the like.

The chief object of this invention is to provide a grain drier with a draft system in which a sufficient velocity of air is created so that the heat gases are forced from the combustion chamber to a heat transfer chamber for mixing with the incoming air.

In the past grain driers of the direct heat type have been operated with a single blower unit, but have been very unsatisfactory and inefficient because the velocity in the heat transfer chamber and in the combustion chamber, were the same, therefore the amount of heat forced into the air stream in the heat transfer chamber was very limited.

The chief feature of this invention resides in a single blower unit and a draft tube so arranged that a pressure differential is created so that the gas from the combustion chamber will be forced from said chamber into the heat transfer chamber and passed into the grain for drying purposes.

Another feature of this invention resides in a heat resisting screen placed over the outlet of the combustion chamber for trapping any combustible material that may pass through the draft tube and into said chamber. This safety factor is of the greatest importance.

The full nature of the invention will be understood from the accompanying drawings and the following description and claim.

In the drawings,

Fig. 1 is a top plan view of the invention with parts broken away to show other parts in detail.

Fig. 2 is a side elevational view with parts shown in section.

Fig. 3 is a transverse sectional view of a modifled form of the invention.

In Fig. 1, I indicates a blower unit preferably of the center disk type construction having forward or backward curved blades I I, a center disk I2 and blower shaft I3, said shaft having a pulley I4 mounted on one end thereof and driven by a power unit I5 through belt I6. Mounted on the other end of said shaft is a pulley II which drives a fuel pump I8 through belt I9. Connected to and directly in front of the blower I0 is the drier housing 20 having the parts thereof to be described later.

The horizontal runners 2| support the housing 20 by the legs 22 and cross-members 23 and the blower unit is supported by the legs 24 and crossmembers 25. 1

In Fig. 2, 20 indicates the drier housing having 1 Claim. (Cl. 263-19) 2 ,1 in the upper portion and extending downwardly at the extreme end thereof a draft tube 26 with a damper 21 in the upper portion. A fuel burning unit 28 is positioned in the remote end of said tube and at the mouth of the combustion chamber 29. The combustion chamber located in the lower part of the drier housing has a heat resisting metal screen 30 at the heat discharge opening or outlet 30a. This chamber is'surrounded by a cooling duct 3|, the air being directed into said duct by the baflie plate 32. Also within the drier housing is a heat transfer chamber 33 having attached-to its remote end a heat conduit 34 which may be of canvas orcloth material, for conveying the heat to the material to be dried. In Fig. 3, I20 indicates a drier housing having a heat transfer chamber I33 in the upper portion and a combustion chamber I29 in the lower portion thereof. Said combustion chamber has a fuel burner and at the heat discharge opening I30a a heat resisting metalscreen I30. A heat exchange tube I35 is rigidly secured above'the opening I30a and said tube passes through the drier housing at I36 and terminates at the exhaust stack I3'I.

The grain drier operates as follows by wayof example only: when oil is used as a source of heat, the oil is supplied under pressure to the combustion chamber 29 by means of a pump I8 which is driven by belt I9 from the blower shaft I3. Therefore in case of, power failure the flow of oil will immediately stop.

In this drier a single blower I0 maybe used to furnish both the air to be heated for drying and the air for the combustion chamber. Since the combustion chamber is between the blower and the material being dried, and the products from the combustion chamber are allowed to enter the drying air, it is necessary to create a higher pressure in the chamber 29 than at its outlet 30a.

This critical pressure differential is accomplished by the use of a center disk type blower.

I2 and a properly placed draft tube 26. The draft tube which conducts a portion of the air to the combustion chamber is located forwardly of and directly in front of the center disk. As the air enters both sides of the blower the momentum of the movement causes a portion of the air to accumulate in the middle at the center disk. Therefore when the air leaves the blower the velocity on either side of the disk is much greater than the velocity of the air between the disk and the openings of the blower. The placing of the draft tube in the path of the high velocity air 3 stream thus forces a great amount of air unde pressure to the combustion chamber. In as much as the air required in the combustion chamber is much less than that supplied to the open end of the draft tube, the velocity pressure is changed to static pressure in sufficient amounts to increase the pressure in the combustion chamber and force its contents into the air stream passing from the blower into the heat transfer chamber and on into the grain being'dried. A valve or damper is installed in said draft tube for the control of the velocity pressure of the air passing into the combustion chamber to insure proper combustion.

At the heat outlet of the combustion chamber,

there is placed a heat resisting metal screen 30 which assumes approximately the temperature of the escaping heat gases. This screen holds in the combustion chamber until burned any material that has found its way into said chamber. The screen by assuming approximately the same temperature as that of the escaping gases will not become clogged but will burn itself clean and the ashes may drop down into the combustion chamber.

In this. direct drier device the products of combustion are directed into the drying air stream in order that all of the heat. will be furnishedfor drying and very little lost to the atmosphere. This device operates with very high efficiency- In themodified form of the invention the heat gases are directed from the combustion chamber into a heat. exchanger tube I35 having a heat resisting metal screen I30. therein extending through the side wall of the heat transfer chamberand said tube I33 as at I36 and terminating atv the exhaust stack I 3I. The air directed into the heat transfer chamber by the blower unit is heated by the transfer of heat through the walls of said exchanger tube and the combustion chamber walls. This is an indirect type drier.

This modified form may be converted into a direct type drier by extending or directing the tube I35 to the intake port of thev blower unit thereby pulling into the. drier any of the escaping heat gases.

The efliciency of pulling the clean air through the blower for mixing with the heat gases is an increase in air volume of approximately ten percent over the system in which the heated air is moved or circulated by the blower.

A safe and efficient drier which reduces the moisture content of the grain will bring the following advantages to the farmers: Corn can be picked much earlier when weather conditions are. better for working in the field, thus reducing the strain on the farmer and his machinery by hurried last. minute rushes to get the crops in before bad weather. In early picking, less corn is left in the field because of bent-over stalks. When corn is picked early, wheat can be sown to. better advantage. after the corn which early planting is of great importance.

While the invention has been illustrated and described in great detail in the drawings and foregoingv description, the same is 'to be considered as illustrative and not restrictive in character.

The several modifications described herein as well as others which will readily suggest themselves to persons skilled in this art, all are considered to be within the broad scope of the invention, reference being had to the appended claim.

The invention claimed is:

A device for drying grain in a crib or the like, comprising a blower unit of center disc type, driving means for said unit, a drier housing disposed forwardly of said unit, a substantially horizontal heat transfer chamber disposed in said housing and in communication with said blower unit, a flexible conduit in communication with said heat transfer chamber and connected to said housing at the forward end thereof remote from said blower unit, said conduit being adapted for communication with a grain crib or the like, a combustion chamber disposed within said housing, the upper wall of said combustion chamber being adjacent said heat transfer chamber, a substantially L-shaped draft tube disposed within said housing and being in communication with said blower unit, the arm of said substantially L-shaped tube being parallel to the axis of said heat transfer chamber and lying at the upper end thereof, the base of said substantially L- shaped tube extending downwardly adjacent the forward end of said heat transfer chamber and having a discharge outlet adjacent the free end thereof, said discharge outlet being in communication with said combustion chamber. a burner unit mounted intermediate said combustion chamber and the discharge end of said tube, said combustion chamber having a discharge outlet formed in the upper wall thereof adjacent the rearward portion of said heat transfer chamber and in communication therewith, a, heat resisting screen positionedat the mouth of said combustion chamber outlet, and a cooling tube disposed within said housing. contiguous to said combustion chamber, the side and bottom walls of said combustion chamber forming one wall of said cooling tube.

ROBERT D.' APPLEGATE.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS France Apr. 22, 1940 

